I cannot center my archives pages

Look my web page: https://redtalentohumano.ec/2013/04/10/ only archives float to left, and I try all, use cuestom CSS, edit the responsive.css of the buddypress default folder, even use a plugin to change my style css but nothing, I cant margin my web to center: https://img90.xooimage.com/files/e/c/2/archives-3d5ac16.png